Quick connect couplings or fittings are well known in the art and various types are described in U.S. patents. For example, U.S. Pat. Nos. 4,565,392, 4,063,760, 3,540,760 and 3,479,068 disclose couplings of this general type, which are attached to metal tubes or flexible hoses for making fluid connections. In such a coupling, a tubular nipple part is inserted into a tubular socket part, and a resilient O-ring extends between the two parts and forms a seal. Upon insertion, the two parts become locked in assembled relation by a split lock ring or snap ring which is located in radially aligned lock grooves formed in the two parts. Prior to the assembly of the two parts, the snap ring is loosely positioned in the lock groove of the outer socket. When the nipple is inserted into the socket, the forward end of the nipple passes through and expands the snap ring, and the assembly is completed when the snap ring "snaps" into the lock groove of the nipple. The snap ring then extends into both grooves, thereby locking the parts together.
Couplings of this character have been used, for example, in making hydraulic connections in automobiles and trucks, such as the connections between the engine block and an oil cooler. An automobile or truck is constructed on a moving assembly line, and workers at stations along the line make the connections while the line is moving. It is, of course, very important, because the line moves continuously, that the socket and the nipple be securely connected together very easily and rapidly. There have been instances where the cut ends of a split snap ring have snagged on the insert part during assembly and increased the time required to make a secure connection.
Quick connect couplings have also been provided which include an annular garter spring in place of a split snap ring. Examples of such couplings are shown in U.S. Pat. Nos. 2,693,378, 4,055,359, 4,376,525 and 4,401,326. See also Canadian patent No. 637,102. While a garter spring has an advantage over a split ring in that it does not have ends which may catch on the nipple part during assembly of the coupling, this advantage has been offset by other disadvantages in prior art fittings. These disadvantages are derived from that fact that a garter spring is formed by a coiled small diameter wire which has its ends connected together to form an endless loop. The connected ends of the wire may come loose or the thin wire may break at some other point during use, thereby releasing the locked connection between the coupling parts. Further, if the internal fluid pressure in a coupling is very high, the coils of the wire may flatten sufficiently that the coupling parts may become disconnected.
It is a general object of the present invention to provide an improved quick connect coupling including a garter spring, which avoids the foregoing disadvantages.